fix: ret invalid cred if usr not found in login

apps/backend/internal/user/service.go

@@ -5,6 +5,8 @@ import (
 	"database/sql"
 	"errors"
 
+	"github.com/get-drexa/drexa/internal/database"
+	"github.com/get-drexa/drexa/internal/password"
 	"github.com/google/uuid"
 	"github.com/uptrace/bun"
 )
@@ -13,20 +15,60 @@ type Service struct {
 	db *bun.DB
 }
 
+type UserRegistrationOptions struct {
+	Email       string
+	DisplayName string
+	Password    password.Hashed
+}
+
 func NewService(db *bun.DB) *Service {
 	return &Service{
 		db: db,
 	}
 }
 
+func (s *Service) RegisterUser(ctx context.Context, opts UserRegistrationOptions) (*User, error) {
+	u := User{
+		Email:       opts.Email,
+		DisplayName: opts.DisplayName,
+		Password:    opts.Password,
+	}
+
+	_, err := s.db.NewInsert().Model(&u).Returning("*").Exec(ctx)
+	if err != nil {
+		if database.IsUniqueViolation(err) {
+			return nil, newAlreadyExistsError(u.Email)
+		}
+		return nil, err
+	}
+
+	return &u, nil
+}
+
 func (s *Service) UserByID(ctx context.Context, id uuid.UUID) (*User, error) {
 	var user User
 	err := s.db.NewSelect().Model(&user).Where("id = ?", id).Scan(ctx)
 	if err != nil {
 		if errors.Is(err, sql.ErrNoRows) {
-			return nil, newNotFoundError(id)
+			return nil, newNotFoundError(id, "")
 		}
 		return nil, err
 	}
 	return &user, nil
 }
+
+func (s *Service) UserByEmail(ctx context.Context, email string) (*User, error) {
+	var user User
+	err := s.db.NewSelect().Model(&user).Where("email = ?", email).Scan(ctx)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, newNotFoundError(uuid.Nil, email)
+		}
+		return nil, err
+	}
+	return &user, nil
+}
+
+func (s *Service) UserExistsByEmail(ctx context.Context, email string) (bool, error) {
+	return s.db.NewSelect().Model(&User{}).Where("email = ?", email).Exists(ctx)
+}